From fee6ed693ce8d76a9d3eb61f1e6b53c4bc054827 Mon Sep 17 00:00:00 2001
From: Bhargava Shastry <bhargava.shastry@ethereum.org>
Date: Mon, 7 Jun 2021 13:19:54 +0200
Subject: [PATCH] Introduce if-elseif-else statement.

---
 test/tools/ossfuzz/SolidityGenerator.cpp | 58 ++++++++++++++++++------
 test/tools/ossfuzz/SolidityGenerator.h   | 19 +++++++-
 2 files changed, 62 insertions(+), 15 deletions(-)

diff --git a/test/tools/ossfuzz/SolidityGenerator.cpp b/test/tools/ossfuzz/SolidityGenerator.cpp
index 6c19b3279..54ebe5aeb 100644
--- a/test/tools/ossfuzz/SolidityGenerator.cpp
+++ b/test/tools/ossfuzz/SolidityGenerator.cpp
@@ -445,27 +445,58 @@ void IfStmtGenerator::setup()
 	addGenerators(std::move(dependsOn));
 }
 
-string IfStmtGenerator::visit()
+string IfStmtGenerator::conditionalStmt(Condition _cond)
 {
-	ostringstream ifStmt;
+	ostringstream condStmt;
 	ExpressionGenerator exprGen{state};
 	auto boolType = make_shared<BoolType>();
 	pair<SolidityTypePtr, string> boolTypeName = {boolType, {}};
 	auto expression = exprGen.rLValueOrLiteral(boolTypeName);
-	if (expression.has_value())
-		ifStmt << indentation()
-		       << "if ("
-		       << expression.value().second
-		       << ")\n";
+	solAssert(expression.has_value(), "");
+	if (_cond == Condition::IF)
+		condStmt << indentation()
+		         << "if ("
+		         << expression.value().second
+		         << ")\n";
+	else if (_cond == Condition::ELSEIF)
+		condStmt << indentation()
+		         << "else if ("
+		         << expression.value().second
+		         << ")\n";
 	else
-		return "\n";
+		condStmt << indentation()
+		         << "else"
+		         << "\n";
 	// Make sure block stmt generator does not output an unchecked block
 	mutator->generator<BlockStmtGenerator>()->unchecked(false);
-	ostringstream ifBlock;
-	ifBlock << visitChildren();
-	if (ifBlock.str().empty())
-		ifBlock << indentation() << "{ }\n";
-	ifStmt << ifBlock.str();
+	ostringstream condBlock;
+	condBlock << visitChildren();
+	if (condBlock.str().empty())
+		condBlock << indentation() << "{ }\n";
+	condStmt << condBlock.str();
+	return condStmt.str();
+}
+
+string IfStmtGenerator::visit()
+{
+	ostringstream ifStmt;
+	auto numConditionStmts = uRandDist()->distributionOneToN(s_maxConditionalStmts);
+	ifStmt << conditionalStmt(Condition::IF);
+	numConditionStmts--;
+	solAssert(numConditionStmts >= 0, "");
+	while (numConditionStmts > 0)
+	{
+		if (numConditionStmts == 1)
+		{
+			if (uRandDist()->probable(2))
+				ifStmt << conditionalStmt(Condition::ELSEIF);
+			else
+				ifStmt << conditionalStmt(Condition::ELSE);
+		}
+		else
+			ifStmt << conditionalStmt(Condition::ELSEIF);
+		numConditionStmts--;
+	}
 	return ifStmt.str();
 }
 
@@ -523,6 +554,7 @@ string BlockStmtGenerator::visit()
 {
 	if (nestingTooDeep())
 		return indentation() + "{ }\n";
+	ScopeGuard decDepth([&]() { decrementNestingDepth(); });
 	incrementNestingDepth();
 	ostringstream block;
 	if (unchecked() && !m_inUnchecked)
diff --git a/test/tools/ossfuzz/SolidityGenerator.h b/test/tools/ossfuzz/SolidityGenerator.h
index 72813e117..912c35569 100644
--- a/test/tools/ossfuzz/SolidityGenerator.h
+++ b/test/tools/ossfuzz/SolidityGenerator.h
@@ -173,7 +173,7 @@ public:
 	bool operator>=(IntegerType const& _rhs)
 	{
 		return this->signedType == _rhs.signedType &&
-			this->numBits >= _rhs.numBits;
+			this->numBits == _rhs.numBits;
 	}
 	std::string toString() override
 	{
@@ -823,6 +823,10 @@ struct ExpressionGenerator
 	{
 		nestingDepth++;
 	}
+	void decrementNestingDepth()
+	{
+		nestingDepth--;
+	}
 	void resetNestingDepth()
 	{
 		nestingDepth = 0;
@@ -1074,12 +1078,23 @@ public:
 class IfStmtGenerator: public GeneratorBase
 {
 public:
+	enum class Condition
+	{
+		IF,
+		ELSEIF,
+		ELSE
+	};
+
 	explicit IfStmtGenerator(SolidityGenerator* _mutator):
 		GeneratorBase(std::move(_mutator))
 	{}
 	void setup() override;
 	std::string visit() override;
 	std::string name() override { return "If statement generator"; }
+private:
+	std::string conditionalStmt(Condition _cond);
+	static constexpr size_t s_maxConditionalStmts = 5;
+
 };
 
 class AssignmentStmtGenerator: public GeneratorBase
@@ -1160,7 +1175,7 @@ private:
 	bool m_unchecked;
 	bool m_inUnchecked;
 	static constexpr unsigned s_maxStatements = 4;
-	static constexpr unsigned s_maxNestingDepth = 1;
+	static constexpr unsigned s_maxNestingDepth = 10;
 	static constexpr size_t s_uncheckedInvProb = 13;
 };